The trucking industry has for many years used tractor/trailer combinations to transport cargo over the roadways to intended destinations. As shown in FIG. 1, a tractor 10 and a trailer 20 are mechanically coupled together so that the tractor can pull the trailer with its cargo in an efficient and cost-effective manner using mechanical energy provided by a tractor engine 15 located on the tractor 10. A tractor/trailer combination typically also includes numerous electrical subsystems 50 located on the tractor or the trailer which utilize electrical energy provided by a battery 32. The construction of the battery 32 is well-known, conventionally including a plurality of serially-connected rechargeable lead-acid secondary cells (not shown), each including plate-like electrodes (not shown) immersed in an acidic electrolyte solution (not shown). The battery 32 typically is charged by an alternator 34 mechanically driven by the tractor engine 15. A regulator 36 electrically connected to the alternator 34 controls the electric charge provided by the alternator 34 to the battery 32 in a manner known to those skilled in the art.
The electrical subsystems 50 of a vehicle include a cranking system, which is used to start the tractor engine 15. In addition to the battery 32, the cranking system includes a starter which conventionally has a starter motor, an output shaft, a pinion gear connected to the output shaft, a ring gear connected to the engine flywheel, and a starter solenoid, a magnetically-operated actuator which causes the pinion gear to engage the ring gear when the starter solenoid is energized. When engaged and energized, the starter motor turns the pinion gear transferring mechanical energy to the flywheel and turning the engine 15. The starter motor conventionally is engaged and energized through a relay which closes a high current capacity starter circuit running from the battery to the starter motor and the starter solenoid. The relay conventionally is actuated by a switched circuit connected to the battery 32 through a manually operated ignition switch. The ignition switch conventionally includes momentary pushbutton or similar switch.
In addition to the cranking system, electrical subsystems 50 of tractor/trailers increasingly include a number of electrical accessories such as communication systems, audio systems, video systems, microwave ovens, refrigerators, electric heaters, and the like. Other such subsystems may include motors such as a starter, windshield wipers, heater blower, air conditioning systems, etc. Other non-motor electrical components include electronic black boxes, flashers, relays, coils and contacts. Further, the trailer may include electrical components, such as an anti-lock braking system, refrigeration unit, or other components that receive power from the electrical system of the tractor and, more particularly, from the battery 32.
As most motorists and truckers are aware, the electrical components of a vehicle fail from time to time. Notwithstanding the relatively complex electronics onboard modern vehicles, there is still no common diagnostic circuitry for informing a motorist that a specific one of the plurality of electrical components is faulty or is otherwise failing. As a result, the troubleshooting and repair process is oftentimes time-consuming and laborious. More specifically, there is no common diagnostic circuitry for providing advance notice of potential faults in specific ones of the electrical components, which often leads to stranded motorists in need of roadside repairs. For example, modern vehicles generally do not include any means for identifying the impending failure of the alternator which can lead to an improperly charged battery and, in turn, to a vehicle that will not crank.
Since many electrical systems depend on electrical energy supplied by a battery, it is vital that the battery be properly charged. In this regard, the amount of charge that the battery will take is related to the applied charging voltage and the temperature of the battery. For example, a battery should be charged at a lower voltage when hot and at a higher voltage when cold. Unfortunately, alternators commonly used in tractor/trailers and other vehicles do not regulate the battery charging function based upon the temperature at the battery. Thus, batteries in vehicles do not receive optimal charging, thereby decreasing the efficiency of the charging process and potentially adversely affecting the performance of the electrical components of the vehicle that are dependent on the battery.